1000 oaks filters.

[rory]

Anyone have any experience with Thousand Oaks filters , namely the oiii and uhc type.

I see the solar filters seem popular. , but not much info on the oiii / uhc / h beta .

[John]

I was loaned a 1000 Oaks H-Beta filter for a few months by my good friend Mark at Beaufort 

It seemed a nicely executed filter and the transmission charts I've seen for them show around 95% peak transmission and a sharp cut off which is what you want to see in these things. 

I've not been able to see the Horsehead Nebula with it or the Lumicon H-Beta I now have but I can't blame the filters for that !

You don't see 1000 Oaks stuff for sale much over here but I reckon it is good quality stuff, in the Lumicon / Astronomik league.

[rory]

Thanks for that John , My incling was they are pretty high end , I recall the name, particularly in astro books.

But it's hard getting reviews / reports without seeing lots of graphs with lines all over the shop.

Ta john .

[rory]

I picked up this filter today from the seller. He shown me some circular patterns in the filter glass when held up to the light. He told me he thinks it's fine but wanted to point this out. He is letting me try it without parting with any money up front which is fair enough.

I can't recall seeing marks like this on my old filter , anyone she'd some light on what it may be and will I be wasting time waiting for a clear night to try it ?

It resembles a dounut and look oily.

[rory]

I'll whack a piccy on in a bit .

here it is ,its a oiii filter.

[John]

Difficult to tell from that photo but if it's those two sort of circular ripple features I've not see anything like that before. The H-B's i've used put a pinkish cast on everything when looked through in daylight but it was consistent across the filter.

Testing it is going to be tricky - H-B objects are pretty hard to detect even with such a filter !

[rory]

John , I was going to try it on something like m42 , or a p.n to see if there's anything obvious.

I'm not sure what to make of it ?

[John]

John , I was going to try it on something like m42 , or a p.n to see if there's anything obvious.

I'm not sure what to make of it ?

M42 would be worth a try as it's an extended object so you could pan around it and see if there are any changes in contrast due to coating issues with the filter.

[rory]

the more I look at it (rather than through it) I think its a dudd . I can move it across a light source and get different colours .

 definitely not as it should be im sure.

[Peter Drew]

I'm sorry to say I think the filter has degraded, the appearance should be even over the entire surface. The dielectric coatings might have been overexposed to damp.    

[rory]

Peter , thanks. I don't think I'll even wait for a clear night.

I'll contact seller and return it to him.